Hydraulic brake apparatus for a vehicle

A hydraulic brake apparatus for a vehicle comprising:

• a brake operating member;
• a reservoir containing brake fluid;
• a master cylinder that generates a brake hydraulic pressure by increasing a pressure of the brake fluid from the reservoir;
• a master piston provided in the master cylinder and movable in response to operation of the brake operating member;
• a closed chamber defined at least in part by the master piston;
• a power piston disposed behind the master piston;
• a power chamber defined at least in part by the power piston at a rear portion of the power piston;
• an auxiliary hydraulic pressure source that generates a power hydraulic pressure by increasing the brake fluid from the reservoir to a predetermined hydraulic pressure;
• a pressure regulating device connected to the auxiliary hydraulic pressure source and the reservoir, and that regulates the power hydraulic pressure output from the auxiliary hydraulic pressure source to a predetermined hydraulic pressure and feeds the regulated power hydraulic pressure to the power chamber;
• a reaction disc disposed at a front end portion of the power piston between the power piston and the master piston, and facing towards the closed chamber;
• an intermediate member disposed between the master piston and the power piston to maintain the reaction disc at a position exposed towards the closed chamber;
• and
• the master piston directly transferring a rearwardly directed reaction force to the front end portion of the power piston while bypassing the reaction force member.